Phase sequence voltage amplitude comparison-based failure phase selection method and device

Abstract

The invention relates to a phase sequence voltage amplitude comparison-based failure phase selection method and device. The phase sequence voltage amplitude comparison-based failure phase selection method comprises the steps of: identifying a failure phase according to an amplitude value of an A, B and C three-phase voltage component and a relative size of a positive sequence voltage component amplitude; if a negative sequence voltage component is zero, judging that the negative sequence voltage component is in a state of three-phase symmetrical short-circuit; if a zero sequence voltage component is zero, judging that the zero sequence voltage component is in a state of alternating earth-free short-circuit, identifying the failure phase by using characteristics that a failure phase voltage amplitude value is less than a positive sequence voltage amplitude and a non-failure phase voltage amplitude is more than a positive sequence voltage amplitude; and if the zero sequence voltage component is not zero, judging that the zero sequence voltage component is in a state of earth short-circuit failure, and identifying the failure phase by using characteristics that the failure phase voltage amplitude is less than the positive sequence voltage amplitude and the non-failure phase voltage amplitude is more than the positive sequence voltage amplitude. The invention is suitable for alternating current short-circuit failure phase selection of an inverter station side of an alternating current and direct current hybrid power grid, and makes up the defect of misjudgment of the traditional phase selection element possibly existing in the inverter station side; and auxiliary criterions are not needed in a phase selection process, thus the reliability and the phase selection speed are greatly improved.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a fault phase selection method and device thereof based on phase sequence voltage amplitude comparison. Background technique [0002] In recent decades, my country's DC transmission has experienced a stage of rapid development. The complexity of the structure and operating characteristics of the AC-DC hybrid power grid has significantly increased the difficulty of security control. At present, the commonly used phase selection components mainly include phase selection of sudden change in phase current difference ("Power System Relay Protection". Beijing: China Electric Power Press, 2005.) and sequence current component phase selection ("A New Type of Sequence Component High Voltage Line Protection Phase Selection Components". Electric Power System Automation, 2007, 31 (12): 64-67.), etc. However, the nonlinearity of the DC converter station has a negative impact on the existing relay...

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Problems solved by technology

At present, the commonly used phase selection components mainly include phase selection of sudden change in phase current difference ("Power System Relay Protection". Beijing: China Electric Power Press, 2005.) and sequence current component phase selection ("A New Type of Sequence Component High Voltage Line Protection Phase Selection Components". Electric Power System Automation, 2007, 31 (12): 64-67.), etc. However, the nonlinearity of the DC converter station has a negative impact on the existing relay protection devices. When the AC at the receiving end When the system is weak, the short circuit of the AC outgoing line at the inverter station side may cause continuous commutation failure of the inverter, which in turn leads to DC blocking, making a single AC fault have the characteristics of multiple faults

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